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P0420 Diagnostic Trouble Code Discussion for February 2011

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
1996 Chevrolet Impala SS 5.7L Misfire, MIL Lamp on
P0420: Catalyst System Low Efficiency (Bank 1). HEY GUYS, I,ve been working on this car for 3 days straight,even on my birthday.This one is really kicking my butt. Car came in for a N.J. state inspection.Check engine light was glowing.I pulled codes. The first one was a air pump code. No big deal,seized a...
February 04, 2011
2005 Honda Pilot EX 3.5L MIL Lamp on VIN: 2HKYFI8535
P0420: Catalyst Efficiency Below Threshold (Bank 1). I have hear a 2005 Honda pilot with engine light on with code Po420.Call dealer ship they say 80,000 miles is the cut off for free replacement.Alldata is no help, or is the dealer they say replace all three converters.Bunch of money,Alldata says replace rear b...
February 04, 2011
2000 Nissan Sentra GXE 1.8L Cuts out, Stall VIN: 3NICB51D5Y
P0420: Catalyst Efficiency Below Normal. nissan techs,got a problem here I need help with. I got a 2000 Nissan Sentra 1.8l L4, running rich and cutting off at idle when at normal operating temp., have checked mass air flow, ect sensor, back pressure on catalytic, and have replaced iac valve for high ...
February 09, 2011
2003 Hyundai Elantra GLS 2.0L MIL Lamp on VIN: KMHDN45D13
P0420: Catalyst Efficiency Below Normal (Bank 1). Hello. I have a Hyundai here that I wish would just go away and I need your help to make that happen. This car runs great to performance problems, it has a CEL on and some codes. My first code is po420 which is a cat code. I tested the cat and it all test good...
February 11, 2011
2003 Hyundai Elantra GLS 2.0L MIL Lamp on VIN: KMHDN45D13
P0420: Catalyst Efficiency Below Normal (Bank 1). Hello. I have a Hyundai here that I wish would just go away and I need your help to make that happen. This car runs great to performance problems, it has a CEL on and some codes. My first code is po420 which is a cat code. I tested the cat and it all test good...
February 14, 2011
2003 Toyota Highlander 2.4L MIL Lamp on VIN: JTEGD21A53
P0420: Catalyst Efficiency Below Normal (Bank 1). Hey guys, I've got a good one. This 03 highlander has a couple of problems. According to the scanner this vehicle is running very lean ... 24% short term fuel trim (after being reset) and the long term follows it. I have checked the MaF which is clean, fairly ...
February 15, 2011
1997 Mercury Grand Marquis LS 4.6L MIL Lamp on VIN: 2MELM75WXV
P0420: Bank 1 catalyst underperforming. There is a TSB # 03245 for this problem. Could someone tell me what the repair is from this bulletin or email me a copy. Thank you very much. Jon [...]
February 18, 2011
2000 Nissan Sentra GXE 1.8L Stall VIN: 3N1CB51D51
P0420: Catalyst Efficiency Below Normal. Hello, we have a 2000 Nissan Sentra at our shop that is intermittently stalling but will always restart. It came in for this symptom several weeks ago and could only duplicate the concern one time, fuel pressure remained in spec. The vehicle did have 2 Cat eff...
February 18, 2011
2008 Subaru Outback 2.5L vibration VIN: 4S4BP62CX8
P0420: Converter efficency code. ... engine light on and vibration when car is put into gear, P0420, cat effic code, it was test drove and monitored a/f sensors. It was not switching, it was replaced and engine was motor vaced. Client took the car, Ck engine light came back on and P0420 came ...
February 21, 2011
1996 Chevrolet Impala SS 5.7L Misfire, MIL Lamp on
P0420: Catalyst System Low Efficiency (Bank 1). HEY GUYS, I,ve been working on this car for 3 days straight,even on my birthday.This one is really kicking my butt. Car came in for a N.J. state inspection.Check engine light was glowing.I pulled codes. The first one was a air pump code. No big deal,seized a...
February 04, 2011
2005 Honda Pilot EX 3.5L MIL Lamp on VIN: 2HKYFI8535
P0420: Catalyst Efficiency Below Threshold (Bank 1). I have hear a 2005 Honda pilot with engine light on with code Po420.Call dealer ship they say 80,000 miles is the cut off for free replacement.Alldata is no help, or is the dealer they say replace all three converters.Bunch of money,Alldata says replace rear b...
February 04, 2011
2000 Nissan Sentra GXE 1.8L Cuts out, Stall VIN: 3NICB51D5Y
P0420: Catalyst Efficiency Below Normal. nissan techs,got a problem here I need help with. I got a 2000 Nissan Sentra 1.8l L4, running rich and cutting off at idle when at normal operating temp., have checked mass air flow, ect sensor, back pressure on catalytic, and have replaced iac valve for high ...
February 09, 2011
2003 Hyundai Elantra GLS 2.0L MIL Lamp on VIN: KMHDN45D13
P0420: Catalyst Efficiency Below Normal (Bank 1). Hello. I have a Hyundai here that I wish would just go away and I need your help to make that happen. This car runs great to performance problems, it has a CEL on and some codes. My first code is po420 which is a cat code. I tested the cat and it all test good...
February 11, 2011
2003 Hyundai Elantra GLS 2.0L MIL Lamp on VIN: KMHDN45D13
P0420: Catalyst Efficiency Below Normal (Bank 1). Hello. I have a Hyundai here that I wish would just go away and I need your help to make that happen. This car runs great to performance problems, it has a CEL on and some codes. My first code is po420 which is a cat code. I tested the cat and it all test good...
February 14, 2011
2003 Toyota Highlander 2.4L MIL Lamp on VIN: JTEGD21A53
P0420: Catalyst Efficiency Below Normal (Bank 1). Hey guys, I've got a good one. This 03 highlander has a couple of problems. According to the scanner this vehicle is running very lean ... 24% short term fuel trim (after being reset) and the long term follows it. I have checked the MaF which is clean, fairly ...
February 15, 2011
1997 Mercury Grand Marquis LS 4.6L MIL Lamp on VIN: 2MELM75WXV
P0420: Bank 1 catalyst underperforming. There is a TSB # 03245 for this problem. Could someone tell me what the repair is from this bulletin or email me a copy. Thank you very much. Jon [...]
February 18, 2011
2000 Nissan Sentra GXE 1.8L Stall VIN: 3N1CB51D51
P0420: Catalyst Efficiency Below Normal. Hello, we have a 2000 Nissan Sentra at our shop that is intermittently stalling but will always restart. It came in for this symptom several weeks ago and could only duplicate the concern one time, fuel pressure remained in spec. The vehicle did have 2 Cat eff...
February 18, 2011
2008 Subaru Outback 2.5L vibration VIN: 4S4BP62CX8
P0420: Converter efficency code. ... engine light on and vibration when car is put into gear, P0420, cat effic code, it was test drove and monitored a/f sensors. It was not switching, it was replaced and engine was motor vaced. Client took the car, Ck engine light came back on and P0420 came ...
February 21, 2011